Communications may be performed in a wireless communications system using multiple antennas. Multiple antennas may be implemented at a transmitting device and/or a receiving device in a wireless communications system. The use of multiple antennas at the transmitting device and the receiving device may be referred to as multiple-input-multiple-output (MIMO). The multi-antenna communications may be performed using a multi-dimensional antenna configuration. The use of multiple antennas at a transmitting device and/or a receiving device may increase performance in the wireless communications system.
While a multi-dimensional antenna configuration may be implemented for performing wireless communications, the multi-antenna communications are performed based on one-dimensional techniques for performing wireless communications. For example, a one-dimensional codebook structure, feedback scheme, and reference signal (RS) structure may be implemented for multi-antenna communications. These one-dimensional techniques may not provide desired performance for multi-dimensional antenna configurations.